The invention relates to a heat exchanger, a heat pump, a dehumidifier, and dehumidifying method, in particular to a heat exchanger for exchanging heat between two fluids through a third fluid, a heat pump and a dehumidifier provided with such a heat exchanger and to a dehumidifying method by exchanging heat through the third fluid.
In order to exchange heat between large amounts of fluids of a relatively small mutual temperature difference, for instance between air conditioning process air and ambient air for cooling, a rotary type heat exchanger of a large capacity and a cross flow heat exchanger 3 as shown in FIG. 49 have been used. Such heat exchangers have been used for instance in a desiccant air conditioning system to cool in advance process air A to be introduced into a room using ambient air B before such introduction occurs.
Such conventional heat exchangers have problems in that they are large in volume and take up too large an installation area, and that heat cannot be utilized sufficiently due to poor heat exchange efficiency.
Therefore, the object of the invention is to provide a heat exchanger of a high heat exchange efficiency with a small size relative to its large heat exchanging duty.
The heat exchanger of the invention comprises a first compartment for flowing a first fluid; a second compartment for flowing a second fluid; a first fluid passage passing through the first compartment for flowing a third fluid for exchanging heat with the first fluid; and a second fluid passage passing through the second compartment for flowing the third fluid for exchanging heat with the second fluid; and is configured such that the first and second flow passages are formed as an integral flow passage, the third fluid flows through from the first flow passage to the second flow passage, the third fluid evaporates on the heat transfer surface located on the flow passage side of the first flow passage at a specific pressure, and condenses on the heat transfer surface located on the flow passage side of the second flow passage at approximately the specific pressure.
With such configuration described above, since the third fluid, or a refrigerant for example, flows from the first to the second fluid passages it can transfer heat from the first to the second compartment. Since the third fluid evaporates at the specific pressure on the heat transfer surface located on the flow path side of the first flow passage, the third fluid can take heat from the first fluid. Since the third fluid 250 condenses at almost the specific pressure on the heat transfer surface located on the flow path side of the second flow path, the third fluid can give heat to the second fluid. Since the above-mentioned heat transfer is evaporating heat transfer or condensing heat transfer, the heat transfer coefficient is much higher in comparison with only heat transfer by conduction or convection. Since the first and second flow passages are made as an integral body, arrangement as a whole is made compact. In the description above, the expression of xe2x80x9cat almost the specific condensing pressurexe2x80x9d is used because a flow is present from the first to the second flow passages, and there is a flow loss even though it is very small. Substantially, the pressure can be deemed to be the same.
With another configuration in which the second fluid contains moisture, the efficiency of cooling the third fluid by means of the second fluid can be enhanced by utilizing the latent heat of evaporation of water.
With still another configuration in which a third fluid passage for flowing the third fluid for exchanging heat with the second fluid is additionally arranged parallel to the second flow passage and passes through the second compartment, and in which the third fluid substantially bypasses the first compartment and is supplied to the third flow passage and flows through the second compartment, it allows the third fluid to be of a phase different from the phase of the third fluid flowing through the first fluid passage to flow through the third flow passage.
It may also be configured such that the third fluid in liquid phase is introduced to the first flow passage and the third fluid in vapor phase is introduced to the third flow passage. For example, the fluid is separated into vapor phase and liquid phase using a vapor-liquid separator. In this way, it is possible to evaporate the liquid-phase third fluid in the first flow passage, and condense the vapor-phase third liquid in the third flow passage.
Another heat exchanger of the invention is configured such that a plurality of the first passages are disposed with different evaporating pressures in the respective passages. With such a configuration, pressures in the plurality of flow passages are arranged in the high to low or low to high order of the different pressures in the plurality of flow passages according to the temperature changes of the first fluid flowing through the first compartment or of the second fluid flowing through the second compartment. With such a configuration, the plurality of flow passages in which evaporation or condensation occurs at different pressures are arranged for example in the order of high to low pressure. Therefore, for example, in case the first fluid is deprived of sensible heat, temperature of the first fluid lowers during the time it enters and exits the first compartment. If the specific temperatures are arranged in the high to low order according to the temperature drop, heat exchange efficiency can be enhanced. This, in turn, enables effective use of heat. In other words, a plurality of flow passages are arranged such that the first and second fluids flow in normal and reverse directions, respectively. In this way, the first and second fluids flow in a counterflow manner to each other.
The heat pump of the invention comprises a pressure raiser for raising the pressure of a refrigerant; a first heat exchanger for condensing the refrigerant whose pressure has been boosted with the pressure raiser by taking heat from the refrigerant with a high temperature fluid under a first pressure; a first throttle for reducing to a second pressure the refrigerant that has been condensed with the first heat exchanger; a second heat exchanger for evaporating the refrigerant that has been reduced in pressure with the first throttle by the heat from the first fluid under the second pressure, and for condensing the refrigerant, after the evaporation, by taking heat from the refrigerant with a second fluid; a second throttle for reducing the pressure of the refrigerant to a third pressure, after being condensed with the second heat exchanger; and a third heat exchanger for evaporating the refrigerant that has been reduced in pressure with the second throttle, by imparting heat from low temperature fluid under the third pressure. With such a configuration, since the second heat exchanger is provided for performing heat exchange utilizing the evaporation and condensation of the refrigerant, heat can be exchanged between the first and the second fluids with a high heat exchange efficiency. Incidentally, while the word xe2x80x9cpressure raiserxe2x80x9d in the above description typically refers to the compressor for compressing the refrigerant in vapor phase, it can also refer to a device comprising for example, an absorber that can be installed in an absorption refrigerator, a lean absorption pump for pumping up lean solution which has absorbed refrigerant in the absorber, and a generator for generating the refrigerant from lean solution pumped up with the pump.
A dehumidifier of the invention comprises a moisture adsorber containing a desiccant for adsorbing moisture in the process air; and a process air cooler for cooling the process air from which moisture has been adsorbed with the desiccant. The process air cooler is configured to cool the process air by the evaporation of the refrigerant and to cool and condense the evaporated refrigerant by means of a cooling fluid in the process air cooler.
The evaporated refrigerant is condensed typically by cooling with the cooling fluid on the downstream side as it flows in one direction as a whole in the process air cooler. The phrase xe2x80x9cin one direction as a wholexe2x80x9d refers to the fact that the vapor and also the liquid phase refrigerant as a whole flow in the same direction, although there may be local reverse eddies if the flow is turbulent.
A dehumidifying method of the invention comprises a first step of cooling the process air with a refrigerant that evaporates at a low pressure; a second step of raising to a high pressure the pressure of the refrigerant that has evaporated in the first step; a third step of heating regeneration air for regenerating the desiccant with the refrigerant that condenses at the high pressure; a fourth step of regenerating the desiccant by desorbing moisture from the desiccant with the regeneration air heated in the third step; a fifth step of adsorbing moisture in the process air with the desiccant regenerated in the fourth step; a sixth step of cooling the process air from which moisture has been removed by adsorption in the fifth step, by evaporating the refrigerant that has condensed in the third step at an intermediate pressure between the low and high pressures; and a seventh step of condensing the refrigerant that has evaporated at the intermediate pressure, at a pressure which is approximately the same as the intermediate pressure.
With the dehumidifying method described above, since the so-called economizer cycle can be utilized, the refrigerating effect of the refrigerant can be enhanced and, in its turn, air can be dehumidified with a high COP.
Another dehumidifier of the invention comprises a first refrigerant-air heat exchanger having a first refrigerant inlet-outlet and a second refrigerant inlet-outlet, and for causing heat exchange between the refrigerant and the process air; a compressor having an intake port and a discharge port for taking in and discharging the refrigerant, the second refrigerant inlet-outlet being disposed to be selectively connectable to either the intake port or the discharge port; a second refrigerant-air heat exchanger having a third refrigerant inlet-outlet and a fourth refrigerant inlet-outlet and for causing heat exchange between the refrigerant and the process air, with either the intake or discharge port whichever has not been connected to the second refrigerant inlet-outlet, being disposed to be connectable to the third refrigerant inlet-outlet; and a third refrigerant-air heat exchanger disposed on the upstream side of the process air flow through the first refrigerant-air heat exchanger, having a fifth refrigerant inlet-outlet and a sixth refrigerant inlet-outlet and for causing heat exchange between the process air, the refrigerant and the cooling fluid, with the fourth refrigerant inlet-outlet being disposed to be connectable to either the fifth refrigerant inlet-outlet or the sixth refrigerant inlet-outlet; and a moisture adsorber disposed on the upstream side of the process air flow passing through the third refrigerant-air heat exchanger and having a desiccant for adsorbing moisture in the process air; and is configured such that whichever of the fifth refrigerant inlet-outlet or the sixth refrigerant inlet-outlet that has not been connected to the fourth refrigerant inlet-outlet is connected to the first refrigerant inlet-outlet; when the fourth refrigerant inlet-outlet and the fifth refrigerant inlet-outlet are interconnected, the third refrigerant-air heat exchanger cools the process air passing through the third refrigerant-air heat exchanger by the evaporation of the refrigerant supplied from the fourth refrigerant inlet-outlet to the fifth refrigerant inlet-outlet, and cools and condenses the evaporated refrigerant with the cooling fluid, so that the condensed refrigerant can be supplied to the first refrigerant-air heat exchanger.
In that case, since devices are arranged to permit selective connections, the operation mode of the dehumidifier can be changed.
Still another dehumidifier of the invention comprises a moisture adsorber having a desiccant for adsorbing moisture in the process air; and a process air cooler, disposed on the downstream side of the process air flow relative to the moisture adsorber, for cooling the process air from which moisture has been adsorbed with the desiccant; and is configured such that the process air cooler cools the process air by the evaporation of the refrigerant and condenses the evaporated refrigerant in the process air cooler; and the process air cooler has a plurality of evaporating pressures of the process air cooling refrigerant and, corresponding thereto, a plurality of condensing pressures at which the refrigerant is cooled and condensed with the cooling fluid. In that case, since there are a plurality of refrigerant evaporating pressures and, corresponding thereto, a plurality of refrigerant condensing pressures, and since the plurality of evaporating pressures are set to be different from each other, the plurality of evaporating pressures and condensing pressures can be arranged in the high to low order or low to high. This makes it possible to perform the heat exchange between the process air and the cooling fluid in almost the so-called counter flow manner.
Still another dehumidifier of the invention comprises a moisture adsorber having a desiccant which adsorbs moisture from the process air and which is regenerated with the regeneration air; a heat pump, having a compressor for compressing a refrigerant, for pumping up heat from a low temperature heat source to a high temperature heat source using the process air as the low temperature heat source and the regeneration air as the high temperature heat source; and a process air cooler for cooling the process air from which moisture has been removed by adsorption with the desiccant; and is configured such that the refrigerant, before being drawn into the compressor, is heated with the refrigerant after being compressed with the compressor and after it has exchanged heat with the regeneration air before regenerating the desiccant. In that case, since the refrigerant before being drawn into the compressor is heated with the refrigerant after being compressed with the compressor and after exchanging heat with the regeneration air before it has regenerated the desiccant, that is, the refrigerant in an almost saturated state before being drawn into the compressor can be heated with the refrigerant which has exchanged heat, the discharge temperature of the refrigerant compressed with the compressor increases, which in its turn permits the increase of the regeneration air temperature.
Still another dehumidifier of the invention comprises a moisture adsorber having a desiccant for adsorbing moisture which in turn is desorbed with regeneration air; a first heat pump for pumping up heat from a first evaporation temperature to a first condensation temperature by circulating a refrigerant and configured to condense the refrigerant, after evaporating the refrigerant at a first intermediate temperature between the first condensation temperature and the first evaporation temperature, at a temperature which is almost equal to the first intermediate temperature; and a second heat pump for pumping up heat from a second evaporation temperature which is lower than the first evaporation temperature to a second condensation temperature which is lower than the first condensation temperature by circulating a refrigerant and configured to condense the refrigerant, after evaporating the refrigerant at a second intermediate temperature between the second condensation temperature and the second evaporation temperature, at a temperature which is almost equal to the second intermediate temperature; and is configured such that the process air from which moisture is desorbed with the desiccant is cooled with the refrigerant that evaporates at the higher temperature of the first and the second intermediate temperatures, subsequently is also cooled with the refrigerant which evaporates at the lower intermediate temperature, then is cooled with the refrigerant which evaporates at the first evaporation temperature, and then is cooled with the refrigerant which evaporates at the second evaporation temperature; and the regeneration air is heated with the refrigerant that condenses at either a temperature which is almost equal to the first intermediate temperature or a temperature which is almost equal to the second intermediate temperature whichever lower, then is heated with the refrigerant that condenses at the rest of the two temperatures whichever higher, then is heated with the refrigerant that condenses at the second condensation temperature, then is heated with the refrigerant that condenses at the first condensation temperature, and then the moisture in the desiccant is desorbed with the heated regeneration air.
With the configuration described above, since at least two heat pumps are provided, heat drop through each heat pump is smaller in comparison with a configuration comprising only a single heat pump. Also, since the process air cooler is provided, each heat pump works in the economizer cycle and makes it possible to provide a dehumidifier of a high COP.
Such a dehumidifier may also be configured such that the heat pump is provided with a process air cooler and a condenser, with the condenser disposed in a position vertically above the process air cooler. In that case, since the condensed refrigerant liquid flows downward, the gravitational force as well as refrigerant pressure can be utilized to feed the refrigerant liquid from the condenser to the process air cooler. Therefore, it is suitable for use with the so-called low pressure refrigerant.
A dehumidifier of the invention comprises a first air flow passage having a first intake port at its one end and a first discharge port at its other end so as to permit a first air flow from the first intake port to the first discharge port; and a desiccant wheel through which the first air flow passes, and the rotary shaft of which is disposed vertically; and is configured such that one of the desiccant and the first air flow removes moisture from the other; and the first air flow passage mainly includes a downward flow passage portion extending vertically downward and an upward flow passage portion extending vertically upward.
With such a configuration, since the dehumidifier is provided with the desiccant wheel with its rotary shaft disposed vertically and with the passage of the first air flow mainly including the downward flow passage portion extending vertically downward and the upward flow passage portion extending vertically upward, an orderly arrangement is possible in which the first air flow through the dehumidifier mainly reciprocates vertically, the first air flow need not change its direction immediately before and after the desiccant wheel, and the humidifier is made compact with a small installation compartment due to the vertically arranged major devices.
In still another dehumidifier of the invention, the first intake port is disposed on or in the vicinity of the top surface of the dehumidifier and the first discharge port is disposed on or in the vicinity of the top surface of the dehumidifier. In that case, it is configured that the first air flow runs from the downward flow passage portion to the upward flow passage portion.
Since the first intake port is disposed on or in the vicinity of the top surface of the dehumidifier and the first discharge port is disposed on or in the vicinity of the top surface of the dehumidifier, the space from the top surface or the vicinity of the top surface of the dehumidifier to a position of certain height in the dehumidifier can be utilized as the first air flow passage to simplify the first air flow passage, and to reduce the size and installation area of the dehumidifier.
In still another dehumidifier of the invention, the first intake port is disposed on or in the vicinity of the bottom surface of the dehumidifier and the first discharge port is disposed on or in the vicinity of the bottom surface of the dehumidifier. In that case, the first air flow runs from the upward flow passage portion to the downward flow passage portion.
Since the first intake port is disposed on or in the vicinity of the bottom surface of the dehumidifier and the first discharge port is disposed on or in the vicinity of the bottom surface of the dehumidifier, the space from the bottom surface or the vicinity of the bottom surface of the dehumidifier to a position of certain height in the dehumidifier can be utilized as the first air flow passage to simplify the first air flow passage, and to reduce the installation area.
Still another dehumidifier of the invention comprises a second air flow passage having a second intake port at its one end and a second discharge port at its other end to permit a second air flow from the second intake port to the second discharge port; and is configured such that, in case moisture is removed from the desiccant with the first air flow, the moisture is removed from the desiccant to the second air flow, and that, in case moisture is removed from the desiccant to the first air flow, moisture is removed from the desiccant with the second air flow; and that the second air flow mainly includes a flow passage portion vertically directed upward.
Since the second air flow passage is configured to mainly include the vertically directed upward flow passage portion, both the first and the second air flow passages are directed upward, and the first and the second air flow passages are arranged in good order, the first and the second air flow direction need not be changed immediately before and after the desiccant wheel, major devices may be disposed in a vertical tier with one device over another, and the dehumidifier is made compact to reduce the installation area.
In still another dehumidifier of the invention, the second intake port is disposed on or in the vicinity of the bottom surface of the dehumidifier and the second discharge port is disposed on or in the vicinity of the top surface of the dehumidifier.
Since the second intake port is disposed on or in the vicinity of the bottom surface of the dehumidifier and the second discharge port is disposed on or in the vicinity of the top surface of the dehumidifier, a length almost equal to the height from the bottom to the top surface of the dehumidifier can be utilized as a second air flow passage to make the dehumidifier compact.
Still another dehumidifier of the invention is characterized in that the first air is process air.
Still another dehumidifier of the invention is characterized in that the first air is regeneration air.
Still another dehumidifier of the invention is characterized in that the first air is process air and the second air is regeneration air.
Still another dehumidifier of the invention comprises a first heat exchanger configured to cool the process air and that the desiccant is configured to remove moisture from the process air before the process air is cooled with the first heat exchanger.
Since the desiccant processes the process air before it is cooled with the first heat exchanger, namely since the process air which has passed through the desiccant is cooled with the second heat exchanger, it is possible to maintain a high heat exchange efficiency while making the dehumidifier compact and reducing the installation area.
Still another dehumidifier of the invention comprises a first heat exchanger configured to cool the process air; a second heat exchanger configured to heat the regeneration air; and a heat pump having a low and a high temperature heat sources; and is configured such that the second heat exchanger constitutes the low temperature heat source while the first heat exchanger constitutes the high temperature heat source.
A dehumidifier of the invention comprises a process air blower (which may be a fan, depending on the air flow loss along the air path) for blowing process air; a regeneration air blower for blowing regeneration air; a compressor for compressing a refrigerant; a refrigerant condenser for heating the regeneration air by condensing the compressed refrigerant; a refrigerant evaporator for cooling the process air by evaporating the refrigerant condensed with the refrigerant condenser; and a desiccant wheel having a rotary shaft disposed vertically and a desiccant which is regenerated as the regeneration air heated with the refrigerant condenser passes through the desiccant and the process air is processed as it passes through the desiccant; and the process air blower, the regeneration air blower, and the compressor are located in a position vertically below the desiccant wheel, while the refrigerant condenser is located in a position vertically above the desiccant wheel.
With the configuration described above, in which the rotary shaft of the desiccant wheel is disposed vertically, the process air blower, the regeneration air blower, and the compressor are located in a position vertically below the desiccant wheel, and the refrigerant condenser is located in a position vertically above the desiccant wheel, since the major devices are arranged in the vertical direction, the devices are arranged in a compact size in the horizontal direction and the installation area is reduced. Here, the term xe2x80x9cmajor devicesxe2x80x9d refers to the blowers, the compressor, the desiccant wheel, the refrigerant condenser, and the refrigerant evaporator and the like.
This application is based on the Japanese patent applications enumerated below and the contents of these applications are incorporated herein by reference to constitute part of this application: Patent application 10-199847 filed on Jun. 30, 1998, Patent application 10-207181 filed on Jul. 7, 1998, Patent application 10-218574 filed on Jul. 16, 1998, Patent application 10-332861 filed on Nov. 24, 1998, Patent application 10-333017 filed on Nov. 24, 1998, Patent application 10-345964 filed on Dec. 4, 1998, Patent application 10-250424 filed on Aug. 20, 1998, Patent application 10-250425 filed on Aug. 20, 1998, Patent application 10-274359 filed on Sep. 10, 1998, Patent application 10-286091 filed on Sep. 22, 1998, Patent application 10-280530 filed on Sep. 16, 1998, Patent application 10-283505 filed on Sep. 18, 1998, and Patent application 10-299167 filed on Oct. 6, 1998.
The invention will be more perfectly understood from the following description in details. Further scope of application of the invention will also become clear from the following description in details. However, the detailed description and specific examples are the preferred embodiments of the invention and described only for the purpose of illustration. Various changes and modifications may be made by those skilled in the art within the spirit and scope of the invention.
It is not intended to dedicate any disclosed embodiments to the public, and to the extent any disclosed modifications or alterations may not literally fall within the scope of the claims, they are considered to be part of the invention under the doctrine of equivalents.